Re: SWOP proof standards
Re: SWOP proof standards
- Subject: Re: SWOP proof standards
- From: Ray Maxwell <email@hidden>
- Date: Thu, 28 Jun 2007 11:25:57 -0700
Oakley,
The filters used in a densitometer (I assume that you are using Status T
filters) are optimized to isolate and separate the density of each
ink. This is a good measure to keep a given set of inks and a printing
process constant. These filters are not appropriate for emulating the
response of the human eye. Another way of saying this is that matching
densities when you use different ink sets (ink jet proofing vs offset
press inks) does not say anything about how they will match visually.
This is why most standards are moving to colormeteric spectrophotometer
(i.e. CIELab) readings. SWOP is moving in this direction. CIELab is a
model of human color perception. However, you need a spectrophotometer
and software that can map the measurements into CIELab. It is not
possible to convert density readings into Lab values without knowing the
spectral characteristics of the ink set. You can get a visual match
from different ink sets even when the densities don't match.
Hope this helps,
Ray Maxwell
Oakley Masten wrote:
I need a little help here :)
SWOP Standards 1.30 1.40 1.00 1.60 Correct?
Readings from BIG NAME printer's reference proofs
Epson 1.31 1.56 1.06 1.61
What's up with the M reading?
Their proof looked like it was still short on Magenta.
Kodak approval 1.25 1.35 0.78 1.55
Are these numbers good or should they also match SWOP
?
They definately don't match! Visually or numerically
to each other.
Should they? They should right ?
These were sent with the idea that they would be used
as comparison reference printouts.
Your observations would be greatly appreciated.
Thanks
Oakley
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